Valve mechanism for internal-combustion engines



April 15, 1930. R. H. GERARD 1,754,888

VALVE MECHANISM FOR INTERNAL COMBUSTION ENGINES Filed May 51, 1929 2 Sheets-Sheet l Rim 8 a Q Q TTORNEYS.

R. H. GERARD April 15, 1930.

VALVE MECHANISM FOR INTERNAL COMBUSTION ENGINES Filed May 51, 1929 2 Sheets-Sheet 2 73% INEENTOR. I 4 2% r-Mzz- A TTORNEYS.

Patented Apr. 15, 1930 ROY H. GERARD, OF SAN FRANCISCO, CALIFORNIA VALVE MECHANISM FOR INTERNAL-COMBUSTION ENGINES Application filed May 3 1, 1829. Serial No. 367,255.

This invention relates to a valve mechanism for internal combustion engines, and especially to a combination sleeve and piston valve which is adapted to be placed in the head of an engine.

The object of the present invention is to generally improve and simplify the construction and operation 01'' valve mechanisms of the character described ,to provide an engine head: having a valve chest formed therein, open at opposite ends to eon'nnunicate with an inlet and an exhaust manifold and ported centrally to communicate with an engine cylinder; to mount a sleeve valve within the chest to open and close the port forming a communication between the cylinder and the chest; to mount a piston valve within the sleeve to provide cam actuated means where by reciprocal movement is transmitted to the piston valve; and further to provide means whereby movement of the pistonvstlve is transmitted to actuate the sleeve valve.

The valve mechanism is shown by way of illustration in the accompanying drawings, in which:

Fig. 1 is a central vertical section at the head end of an internal conibustion engine, said view showing the application of the valve mechanism and the cam mechanism whereby it is actuated,

Fig. 2 is a cross section taken on line H-TI Fig. 1,

Fig. 3 is a cross section taken on line IIIIII Fig. 1, said view showing the dust cover removed.

Referring to the drawings in detail, and particularly Fig. 1, A indicates the cylinder of an internal combustion engine, B the power piston mounted therein, and G the head whereby the upper end of the cylinder is closed. The head. is, in this instance, provided with a cylindrical shaped valve chest,

such as indicated: at 2. One end of the chest communicates with an exhaust manifold, genorally indicated at D, an dthe opposite end of the chest communicates with an inlet manifold, generally indicated at E. The head C is provided with. a compression chamber 3, which comirni nicates with the chest ancugh meansof. a port 4-. This; port extended to form an annular groove which completely surrounds the chest so as to apply uniform pressure on the sleeve valve, generally indicated at 5-. This valve is also ported, as shown at 6, and when the ports 4 and 6 register ommunication is made between the compression chamber 3 and the valve chest and with the exhaust or inlet manifold as the case may be.

The sleeve valve is internally bored and ground at one end to form a guideway and support for a piston valve, generally indicated at 7. This valve has movement independent of the sleeve, and also a movement in unison therewith, as will hereinafter be described. In fact, cam actuated means are provided for imparting movement to the piston valve and movement of the piston valve is in turn transmitted to actuate the sleeve valve. This is accomplished as follows:

Cast integral with the sleeve valve 5, and secured thereto by means of radial arms 8, is a hub member 9. Secured to the piston valve/Z, and extending through the hub member 9 is a valve stem 10'. This valve stem extends through the head C and is guided thereby, as shown at 11, and it is connected with a cross head 12, which. is reciprocally mounted in a cross head guide 13. The cross head is actuated by a bell crank, generally indicated at F. This crank is pivotally mounted, as at 14, in a cam shaft housing 15. A cam shaft 16 extends through this hous ing, and this shaft is provided with a pair of cams, shown at 17 and 18.

The bell crankiF is provided with two rollers, one indicated at 17 which cooperates with the cam 17,. and a second roller indicated at 18; which cooperates with a cam 18-. The cams 17 and 18- are complementary. cam 18 has a contour exactly opposite to the cam 17, and thetwo Ctfi'lSKtOg'QllllQl with the cooperating, rollers accordingly function as an internal: cam. The two cams here dir-- closed are preferred, as they can. operate in a smaller space, and it accordingly permits a more compact construct-ion.

The operation of the valve mechanism will be as: follows;

Withthe sleeve velvet and? piston valve 7 f That is,

assuming the position shown in Fig. 1, and with the power piston B moving upwardly, exhaust will take place as the burnt gases are being pushed upwardly and outwardly through the ports 4 and 6, and then through the 'alve chest into the exhaust manifold D. When the exhaust stroke has been completed, the surface on cam 17, indicated at 20, will engage roller 17, and a rocking movement will accordingly be transmitted to the bell crank F, which in turn will transmit reciprocal movement to the cross head 12, piston rod 11 and the piston valve 7. The piston valve will then move from one side of the ports 1 and 6 to the other, no movemez'it of the sleeve valve taking place at that time as the piston valve is freely slidable within the sleeve valve.

With the piston valve on the opposite side of the ports l and 6 communication will b made with the intake manifold and during the downward stroke of the piston the cylinder and the compression chamber 3 will be filled with an explosive mixture. This stroke takes place while the face of cam 17, indicated at 21, engages the rollers 17*. hen the intake stroke has been completed the cam surface indicated at 22 will engage roller 17, and further movement of the bell crank in the direction of arrow a will take place.

A collar 1O secured on the piston rod will at that time engage the hub 9 of the sleeve, and the sleeve and piston valve will accordingly move in unison in the direction of arrow b, thus bringing the ports 6 and 4.- out of register and closing the same.

The compression and firing stroke will the take place. During this period roller 17 is engaged by the cam surfaces, indicated at 23, 24 and while these surfaces engage roller 1? piston rod 11 will first be partially retracted so as to move the piston valve from one side of the port 6 to the other, and while cam face 24; is in engagementwith the roller 17, hub 7 of the piston valve will engage huh 9, and the sleeve 5 and th. piston valve will accordingly move in unison or return to the position shown in Fig. 1. This takes place at the moment the firing stroke has been completed.

Ports l and 6 are thus brought back into register, and the piston valve assumes the correct position to permit the exhaust gases to escape through the ports 4 and 6, and the valve shaft 2, and to enter the exhaust mani fold.

The cam surfaces provided by the other cam have not been described, but this is thou ht unnecessary, as they are reverse or comp ementary to the faces on the cam 17 and as such transmit a positive rocking movement to the bell crank F. This is important as it permits high speed operation, and eliminates springs, etc. Any hammer action between thecollar 10 and the hub 9, or-between the hub 7 of the piston valve and the hub 9 is eliminated as pause periods are formed in the respective cams at the points indicated at 30 and 31. That is, when piston valve 7 is moved in the direction of arrow 6 it stops before the collar 10 actually engages the hub 9, say within one sixty-fourth of an inch of making contact. This position is reached when the pause depression 30 in the cam engages the roller 17". The rise of the cam surface 22 is gradual, hence when the collar 10 engages the end of the hub 9 it is with a slow, easy motion which eliminates all hammer action.

Furthermore it will be noted that the sleeve 5 is cushioned at opposite ends by dashpots, such as indicated at 4.0 and all. These limit the movement of the sleeve and they cushion it.

The valve mechanism shown in the present instance is of a simple, substantial construction, and it is operated by a single mechanism, to wit, the piston rod 10. No springs are required, hence the valve action is positive. The sleeve valve balanced, due to the formation of the annular chamber or port 4, thereby eliminating side thrust and permittin the valves to be operated with comparatively little power. Forthe same reason the life of the valves should be fairly great.

The small size of the sleeve and the piston valve reduces the weight of the moving parts to a negligible amount, particularly when comparison is made with sleeve valves of the type used in the well-known Knight motor etc. Inertia forces are, of course, proportionately reduced.

Another feature of the present structure is the ease with which the valve mechanism as a whole may be removed. If there is any wear between the rocker arm and the cross head, it is merely necessary to remove the dust cover indicated at 50, and unscrew the plug 51. A screw driver may then be entered to ad just the plug shown at 52, thereby adjusting andtaking up wear. If it is desired to remove the valve mechanism as a whole the two hand screws, indicated at 53 are unscrewed. This releases the cross head guide 13, thus permitting this to be lifted upwardly away from the upper end of the bell crank arm. This is accordingly disconnected, and so is the connection between the cross head and the piston rod, as a hook connection is provided. hen these parts are removed, the member 11 may also be removed and the-.piston valve-and sleeve can accordingly be pulled out cndwise. The operation of removing the valve mechanism is accordingly easily accomplished.

' Any type of lubricating system may be employed in conjunction with the sleeve and piston'valve, but as such systems are well known, no illustration thereof is made. Suffice it to say that as the surfaces presented by the valve mechanism are small, it may be readily lubricated and sealed with the oil. Furthermore the sleeve is provided with piston rings, such as shown at 60. These assist in maintaining the seal and as they do not then move over the ports indicated at at, the seal will not be broken and the lubricating problem becomes simple.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In a device of the character described, a cylinder and a head, said head having a valve chest formed therein, said chest having a cylinder port communicating with the cylinder, one end of said valve chest forming an inlet passage and the other end an exhaust passage, an open ended sleeve valve slidably mounted in the chest, said sleeve having a port formed therein, a piston valve slidably mounted within the sleeve valve, means whereby reciprocal movement is imparted to the piston valve to move it from one side to another of the sleeve port, and means whereby movement of the piston valve is transmitted to the sleeve valve to move the port in the sleeve into and out of register with the cylinder port.

2. In a device of the character described, a cylinder and a head, said head having a valve chest formed therein, said chest having a cylinder port communicating with the cylinder, one end of said valve chest form ing an inlet passage and the other end an exhaust passage, an open ended sleeve valve slidably mounted in the chest, said sleeve having a port formed therein, a piston valve slidably mounted within the sleeve valve, a

piston rod connected with the piston valve whereby reciprocal movement is imparted to the piston valve to move it from one side to another of the sleeve port, a hub member on the sleeve valve through which the piston rod extends and in which it is slidably mounted, and a collar on the piston rod, said collar engaging the hub on the sleeve valve and imparting movement to the sleeve valve in one direction to move the sleeve valve port out of register with the cylinder port and said hub adapted to be engaged by the piston valve to move the sleeve valve in the opposite direction to bring the sleeve and cylinder ports into register.

3. In a device of the character described, a cylinder and a head, said head having a valve chest formed therein, said chest having a cylinder port communicating with the cylinder, one end of said valve chest forming an passage, an open ended sleeve valve slidably mounted in the chest, said sleeve having a port formed therein, a piston valve slidably mounted within the sleeve valve, means whereby reciprocal movement is imparted to the piston valve to move it from one side to another of the sleeve port, means whereby movement of the piston valve is transmitted to the sleeve valve to move the port in the sleeve into and out of register with the cylinder port, and means for cushioning movement of the sleeve valve in either direction.

4;. In a device of the character described, a cylinder and a head, said head having a valve chest formed therein, said chest having a cylinder port communicating with the cylinder, one end of said valve chest forming an inlet passage and the other end an exhaust passage, an open ended sleeve valve slidably mounted in the chest, said sleeve having a port formed therein, a piston valve slidably mounted within the sleeve valve, a piston rod connected with the piston valve whereby reciprocal movement is imparted to the piston valve to move it from one side to another of the sleeve port, a hub member on the sleeve valve through which the piston rod extends and in which it is slidably mounted, a collar on the piston rod, said collar engaging the hub on the sleeve valve and imparting movement to the sleeve valve in one direction to move the sleeve valve port out of register with the cylinder port and said hub adapted to be engaged by the piston valve to move the sleeve valve in the opposite direction to bring the sleeve and cylinder ports into register, and means for cushioning movement of the sleeve valve in either direction.

5. In a device of the character described a cylinder and a head, said head having a valve chest formed therein, said chest having a cylinder port communicating with the cylinder, one end of said valve chest forming an inlet passage and the other end an exhaust passage, an open ended sleeve valve slidably mounted in the chest, said sleeve having a port formed therein, a piston valve slidably mounted within the sleeve valve, a piston rod connected with the piston valve whereby reciprocal movement is imparted to the piston valve to move it from one side to another of the sleeve port, a hub member on the sleeve valve through which the piston rod extends and in which it is slidably mounted, a collar on the piston rod, said collar engaging the hub on the sleeve valve and imparting movement to the sleeve valve in one direction to move the sleeve valve port out of register with the cylinder port and said hub adapted to be engaged by the piston valve to move tie sleeve valve in the opposite direction to bring the sleeve and cylinder ports into register, and a dash pot member at each end of the sleeve valve into which the sleeve valve 1nlet passage and the other end an exhaust moves and whereby reciprocal movement of the sleeve valve 1s cuslnoned in either direction.

ROY H. GERARD. 

